When a digital broadcasting reception apparatus is moved outside the coverage area of a physical channel that was being received normally, it becomes unable to receive the broadcast signal on that physical channel. A physical channel here is defined as a single unit with a particular frequency bandwidth. For this reason, heretofore, digital broadcasting reception apparatus has been developed in which broadcast area maps showing the coverage areas of each physical channel can be generated in advance to enable automatic switching to some other receivable physical channel at the current position.
When it detects a new receivable position not included in the broadcast area map, a conventional digital broadcasting reception apparatus enlarges the broadcast area map to a maximal polygon including all of the positions included in the existing broadcast area map and the new position. For this reason, there is the problem that in some cases, such as when the existing broadcast area map and the new position are widely separated, the conventional digital broadcasting reception apparatus may add new positions at which it is not certain that station selection is actually possible to the broadcast area map. In particular, when the actual broadcast area map has an indented shape that cannot be approximated by a convex shape, the conventional digital broadcasting reception apparatus connects the two projecting vertices of the indentation with a line, thereby enlarging the broadcast area map by filling in the indentation. This creates the problem that the conventional digital broadcasting reception apparatus may incorporate indented areas where station selection is not actually possible into the broadcast area map.
Therefore, when the digital broadcasting reception apparatus described in Patent reference 1 detects that reception is not possible in a broadcast area map, it creates an unreceivable area map. In actually performing automatic station selection, the digital broadcasting reception apparatus described in Patent reference 1 refers to the unreceivable area map in conjunction with the broadcast area map in order to exclude the effect of unreceivable areas that have been unnecessarily included in the broadcast area map.